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Sept. 22, 1925, Y 1,554,616

P. E. ARMSTRONG HOLLOW DRILL ROD AND PROCESS 0E MAKING Filed Dec. 8, 1922 INVENTOR ATTORNEY Patented Sept. 22, 1925.

UNITED STATES PATENT OFFICE.

PERCY A. E. ARMSTRONG, OF LOUDONVILLE, YORK, ASSIGNOR TO LUDLUM STEEL COMPANY, OF WATERVLIET, NEW YORK, A CORPORATION OF NEW JERSEY.

, HOLLOW DRILL ROD AND PROCESS OF MAKING.

Application filed December 8, 1922. Serial No. 605,699.

To all whom it may concern:

Be it known that I, PERCY A. E. ARM- STRONG, a subject of the Kin of Great Britain, and a resident of oudonville, county of Albany-and State of New York, have invented a certain new and useful Improvement in Hollow Drill Rods and Processes of Making, of which the following is a specification Part of the subject matter of the present application is divided out of my prior application Serial No. 318,253, filed Aug. 18,

1919, and another part is taken from my prior application Serial No. 528,753, filed Jan. 12, 1922.

According to the present invention, the drill rod or similar tubular body is rolled down from an ingot having its bore formed by casting around a tube, which tube becomes welded in place in the casting or casting and rolling operations, forming an integral part of the ingot and drill rod; and this tube is filled with material, such as sand, prior to the casting operation, the original sand core remaining in place during the rolling operation, as ,well as the casting operation, and being finally removed from the completed drill rod; The term sand is used for convenience to include materials non-frittable under high heat,.

such as sand, finely divided burnt magnesite, talc, flint shot, and the like.

The tube is preferably of mild or low carbon steel and the remainder of the ingot and drill rod of hard or higher carbon steel,

tough and serves to strengthen the drills and to revent cracks in the drills forming or beginning at the bore thereof.

It is of great importance in connection with this invention that the sand filling of the tube remain in place from the commencement of the fabrication until the completion thereof. The bore of the tube is preferably cleaned of all oxides, as by pickling, so as to present a clean metallic surface, and the fi ling material, designated for convenience as sand, is likewise clean and free from oxides, such as iron rust. In this way I am enabled to obtain the necessary bore in a very simple, convenient andaccurate way, to carryout the various operations Without intermediate interruptions, as for filling the tube with sand after casting the ingot, and the oxides, etc, which would be formed within an unfilled tube during the casting operation are avoided, as also the excessively hard caking and fritting of the sand filling, which will occur if iron oxides are present within the bore during the operation of hot rolling, making the final removal of the sand extremely difficult, or in some cases impossible. The sand inthe tube also serves to prevent the tube melting through during the steps of making the casting.

In the drawing, Figs. 1 and 2 are'lon itudinal sections of ingots cast in ingot mol s. Fig. 3 is a perspective view 'of the drill rod and F i 4 is a diagrammatical view showing the rol ing of the drill rod with the sand core in place. In Fi 1, 1Q is the tube of mild steel with its filing of sand 11, and

12 the cast portion of the ingot cast in theingot mold 13 from higher carbon or hard steel. The ends of tube 10 are closed by screw plugs 14, and a rod 15 extends centrally through the sand 11. When this rod (elongated) is removed'after the drill rod is rolled out, the removal of the sand from the bore is facilitated.

In Fig. 2, the tube 10' filled with sand 11 has plugs 14', 14;, forced or driven in place against the compacted sand, and holes 16, 16 are made through tube and plugs, which, when the cast material 12' is poured through the filling cap 17, are filled with the molten metal, making substantially cast pins 18, '18, which firmly hold the plugs 14', 14' during the operation ofrolling down the drill rod, as by passing it in heated condition through rolls 19, 19, Fig. 4. The sand core is then removed from theelongated rolled down. drill rod 20, leaving an open bore 21, as shown in Fig. 3. I

Iclaim: I

1. The process of making tubular bodies,

which comprises providing a tube with bore stops in place, hot rolling the ingot comprisfor welding the tube in place therein and ing the cast metal and included tube'with the the sand for preventing the tube walls from sand in the bore, and removing the sand melting through, treating the ingot and core from the elongated tubular body of reduced for elongation and reduction of cross-section,

6 cross-section so produced.- and withdrawing the elongated rod and 15 2. The process of making tubular bodies, removing the sand from the tubular body which consists in providing a tube with a produced.

core consisting of a metallic rod surrounded In testimony whereof, I have signed my by sand casting an ingot around the tube name hereto. 1 utilizing the heat of the molten material PERCY A. E. ARMSTRONG. 

